2002 Vulcan classic FI engine misses bad

[minst7877]

You might take a look at this thread and see if it may be the culprit.

http://www.vulcanbagger.com/forums/s...und+connection

DC

[macmac]

Originally Posted by minst7877

You might take a look at this thread and see if it may be the culprit.

http://www.vulcanbagger.com/forums/s...und+connection

DC

That is the kind of thing I think he has. This doesn't happen all at once. it happens slowly over time from crud on the wires oxidizing and becoming a HIGH RESISTANCE CONNECTION. Where before the day of the total melt down terminal ends are warped and discolored, wires are turning colors like yellowish tan due to getting too hot.

Then later the grounds are over come the load demands too much and you get a melt down, months after the problem had occurred.

Japanese stators are well known for doing this on the AC and the DC side of the engine harness connector that will break the alt from the engine side of the harness so an engine can just be pulled. The terminal block itself is the PROBLEM there and the too small wire diameter they use to keep things light weight. This is meant to be an example but it also could be the problem.

[05nomader]

I had an intermittent rough idle and backfire problem with my 05 I could see from the spark plug wire tester that the front cylinder wasn’t getting spark consistently it would flat cut out at times so I thought it could be bad spark plug, spark plug wire or coil. So I changed all the plugs even though they looked good but had over 20,000 on them still didn’t fix the problem, then I changed the spark plug wires without removing the gas tank same problem. Now I’m thinking coil or I didn’t get the plug wires in the coils good enough so I pulled the gas tank so I could remove the coils and I did have the plug wires in the coils properly but when removing the coils I pulled the two spade connectors off of the back of the coils inspected and cleaned the connectors although they didn’t look that bad and were not loose, put everything back together and it ran perfect. So the conclusion is I didn’t have good continuity at the spade connector on the back of the coil, I don’t know if you’re experiencing anything like this but if it is I hope this helps.

[ringadingh]

I had the exact same issue, and the spade connecter on one of my coils was the culprit as well. A quick squeeze with some pliers and it was fixed.

[Martinmm]

Friday coming home it would hardly idle but ran fine otherwise. Didn't ride Saturday, went for a 30 min ride Sunday and it ran perfect. I'll pull the tank tonite and check the coil connections. Thanks for your continued support, everyone. Stay tuned.

[tomm]

Had a very similar problem back some time ago on another bike. Turned out to be a bad fuse. Didn't blow. Just cracked internally at one end.

Bike would start and run fine for a while. Then between vibration and heating up, the fuse would develop into a high-impedence short. Bike ran like it was possessed. Let it cool down, and everything would be fine again.

[davidhollinger]

Lots of good info from all the members here. Good luck with it, I hope you get it solved and back to riding.
Nice to see Not So Silent Sam back here too!!!

[Martinmm]

After reading everyone's posts and thinking this has to be a wiring issue I went back once more to check coil connections (thanks ringadingh) and take another look at the throttle body and fuel injectors - particularly the throttle sensor (TS).

I checked the coils and they were fine. To get to the TS I realized there was a lot of stuff crammed above and against the connector. After getting under the coolant hose and other wiring I was able to check the connector for the TS and lo and behold I find one of the wires broken but the insulation was still half connected!
So long story short I soldered the break and taped it up well and test drove it to work and home today and it ran A1!

I had read in the shop manual that failure of the TS or vacuum sensor (shorted or open wire) would cause the ECU to control the DFI from the other sensor that had not failed. What I think happened in my case was the wire break was intermittent and was sending conflicting info to the ECU making it run OK some times and not Ok others. Of interest is that I did not get a trouble code - I should have had a fault code 11 - Throttle sensor failure.

I trust the problem is solved. I want to thank all of you that took the time to offer suggestions, share experiences and encourage me to keep looking.
Cheers.

[ringadingh]

Thats what its all about, sharing and learning. Good to hear you got it fixed.

[id-man]

Nice picture - so that connector was crammed into a tight spot where one would assume it's protected and couldn't possibly be broken, and even when viewed appears at first glance to be intact...that sneaky bastard!

[Martinmm]

Just a quick follow up to say the bike runs A1 since the offending broken wire was discovered. I must admit I had looked at that connector previously and did not see the breach in the insulation then. I suspect the insulation came apart when I went digging around the last time. The wire is very thin and wouldn't take much stress to break.
Again thanks for everyone's help. Martin.